As Human Performance Measurement (HPM) continues to advance, developers are facing unique challenges in emerging environments due to a lack of availability to the right data—information specific to measuring and assessing human performance. Additionally, while simulation-based training utilizes a number of standards and protocols, there is limited guidance for making HPM data available and consistent across devices. This paper discusses on-going efforts that demonstrate the impacts of data availability on trainee assessment capabilities, thereby presenting a data driven case for the importance of HPM data. Additionally, the authors present lessons learned for increasing HPM data availability, including defining performance measures early in the training system development lifecycle and establishing HPM standards.